Battery control circuit

ABSTRACT

A battery control circuit includes an electronic switch, first and second diodes, and first and second batteries. A positive terminal of the first battery is connected to a positive terminal of the second battery through the first diode. A negative terminal of the first battery is connected to a positive terminal of the second battery through the electronic switch, and connected to a negative terminal of the second battery through the second diode. When the electronic switch receives a first control signal, the electronic switch is turned on, the first and second diodes are turned off, and the first and second batteries are connected in series. When the electronic switch receives a second control signal, the electronic switch is turned off, the first and second diodes are turned on, and the first and second batteries are connected in parallel.

BACKGROUND

1. Technical Field

The present disclosure relates to control circuits, and particularly toa battery control circuit.

2. Description of Related Art

Generally, a notebook computer adapts a number of lithium batteriesconnected in series, to supply a fixed operation voltage, such as 11.1volts. When the notebook computer is in a standby state or a sleepstate, the voltage required by the notebook computer will be reduced.However, the lithium batteries continue to offer the fixed operationvoltage, thereby, resulting in energy waste.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present embodiments.Moreover, in the drawings, all the views are schematic, and likereference numerals designate corresponding parts throughout the severalviews.

FIG. 1 is a circuit diagram of a battery control circuit in accordancewith a first embodiment.

FIG. 2 is a circuit diagram of a battery control circuit in accordancewith a second embodiment.

DETAILED DESCRIPTION

The disclosure, including the accompanying drawings, is illustrated byway of example and not by way of limitation. It should be noted thatreferences to “an” or “one” embodiment in this disclosure are notnecessarily to the same embodiment, and such references mean at leastone.

Referring to FIG. 1, a first embodiment of a battery control circuit 10includes an input terminal IN1, two output terminals BAT1+ and BAT1−, anelectronic switch Q1, two batteries B1 and B2, and two diodes D1 and D2.

A positive terminal of the battery B1 is connected to the outputterminal BAT1+, and connected to a cathode of the diode D1. A negativeterminal of the battery B1 is connected to a first terminal of theelectronic switch Q1, and connected to a cathode of the diode D2. Apositive terminal of the battery B2 is connected to a second terminal ofthe electronic switch Q1, and connected to an anode of the diode D1. Anegative terminal of the battery B2 is connected to the output terminalBAT1−, and connected to an anode of the diode D2. A third terminal ofthe electronic switch Q1 is connected to the input terminal IN1, toreceive control signals.

In the present embodiment, the battery control circuit 10 is assembledin a notebook computer (not shown). The input terminal IN1 is connectedto a power management system or a south bridge chip of the notebookcomputer, to receive the control signals from the power managementsystem or the south bridge chip. The output terminals BAT1+ and BAT1−output power to the notebook computer. The batteries B1 and B2 are thesame type rechargeable batteries with the same voltage. The electronicswitch Q1 is an n-channel metal-oxide-semiconductor field-effecttransistor (MOSFET), the first, second, and third terminals of theelectronic switch Q1 are respectively a source, a drain, and a gate.

When the notebook computer is in a working state, the input terminal IN1receives a high level first control signal from the power managementsystem or the south bridge chip. The electronic switch Q1 is turned on,the diodes D1 and D2 are turned off, the batteries B1 and B2 areconnected in series, and voltage output between the output terminalsBAT1+ and BAT1− is equal to a sum of the voltages of the batteries B1and B2.

When the notebook computer is in a standby state or a sleep state, theinput terminal IN1 receives a low level second control signal from thepower management system or the south bridge chip. The electronic switchQ1 is turned off, the diodes D1 and D2 are turned on, the batteries B1and B2 are connected in parallel, and voltage output between the outputterminals BAT1+ and BAT1− is equal to the voltage of each of thebatteries B1 and B2.

When the batteries B1 and B2 are recharged by applied voltage generatedby renewable energy, such as solar energy, the input terminal IN1receives the second control signal from the power management system orthe south bridge chip. The electronic switch Q1 is turned off, thediodes D1 and D2 are turned on, and the batteries B1 and B2 areconnected in parallel. In this condition, when the applied voltage isslightly larger than the voltage of each of the batteries B1 and B2, thebatteries B1 and B2 can be recharged.

Referring to FIG. 2, a second embodiment of a battery control circuit 20includes an input terminal IN2, two output terminals BAT2+ and BAT2−,two electronic switches Q2 and Q3, three batteries B3-B5, and fourdiodes D3-D6.

A positive terminal of the battery B3 is connected to the outputterminal BAT2+, and connected to cathodes of the diodes D3 and D4. Anegative terminal of the battery B3 is connected to a first terminal ofthe electronic switch Q2, and connected to a cathode of the diode D5. Apositive terminal of the battery B4 is connected to a second terminal ofthe electronic switch Q2, and connected to an anode of the diode D3. Anegative terminal of the battery B4 is connected to a first terminal ofthe electronic switch Q3, and connected to a cathode of the diode D6. Apositive terminal of the battery B5 is connected to a second terminal ofthe electronic switch Q3, and connected to an anode of the diode D4. Anegative terminal of the battery B5 is connected to the output terminalBAT2−, and connected to anodes of the diodes D5 and D6. Third terminalsof the electronic switches Q2 and Q3 are connected to the input terminalIN2, to receive control signals.

In the present embodiment, the battery control circuit 20 is assembledin a notebook computer (not shown). The input terminal IN2 is connectedto a power management system or a south bridge chip of the notebookcomputer, to receive the control signals from the power managementsystem or the south bridge chip. The output terminals BAT2+ and BAT2−output power to the notebook computer. The batteries B3-B5 are the sametype rechargeable batteries with the same voltage. The electronicswitches Q2 and Q3 are n-channel MOSFETs, the first, second, and thirdterminals of each of the electronic switches Q2 and Q3 are respectivelya source, a drain, and a gate.

When the notebook computer is in a working state, the input terminal IN2receives a high level first control signal from the power managementsystem or the south bridge chip. The electronic switches Q2 and Q3 areturned on, the diodes D3-D6 are turned off, the batteries B3-B5 areconnected in series, and voltage output between the output terminalsBAT2+ and BAT2− is equal to a sum of the voltages of the batteriesB3-B5.

When the notebook computer is in a standby state or a sleep state, theinput terminal IN2 receives a low level second control signal from thepower management system or the south bridge chip. The electronicswitches Q2 and Q3 are turned off, the diodes D3-D6 are turned on, thebatteries B3-B5 are connected in parallel, and voltage output betweenthe output terminals BAT2+ and BAT2− is equal to the voltage of each ofthe batteries B3-B5.

When the batteries B3-B5 are recharged by applied voltage generated byrenewable energy, such as solar energy, the input terminal IN2 receivesthe second control signal from the power management system or the southbridge chip. The electronic switches Q2 and Q3 are turned off, thediodes D3-D6 are turned on, and the batteries B3-B5 are connected inparallel. In this condition, when the applied voltage is slightly largerthan the voltage of each of the batteries B3-B5, the batteries B3-B5 canbe recharged.

In other embodiments, the battery control circuits 10 and 20 may beassembled in other electronic devices employing a plurality of batteriesto supply power. The input terminals IN1 and IN2 are connected to apower management system of the electronic devices to receive controlsignals. The electronic switches Q1-Q3 may be p-channel MOSFETs, ortransistors, or other switches having similar functions, and voltagelevels of the first and second control signals can be adjusted accordingto actual need. Further, in the other embodiments, the number of thebatteries included in each of the battery control circuits 10 and 20 canbe adjusted according to actual need. When adding one battery in each ofthe battery control circuits 10 and 20, the number of the electronicswitches should be added one and the number of the diodes should beadded two accordingly.

It is to be understood, however, that even though numerouscharacteristics and advantages of the embodiments have been set forth inthe foregoing description, together with details of the structure andfunction of the embodiments, the disclosure is illustrative only, andchanges may be made in details, especially in matters of shape, size,and arrangement of parts within the principles of the embodiments to thefull extent indicated by the broad general meaning of the terms in whichthe appended claims are expressed.

What is claimed is:
 1. A battery control circuit comprising: an inputterminal to receive control signals; first and second output terminalsto output power; first and second diodes; an electronic switchcomprising a first terminal connected to the input terminal, a secondterminal, and a third terminal; a first battery comprising a positiveterminal connected to the first output terminal and a cathode of thefirst diode, and a negative terminal connected to the second terminal ofthe electronic switch and a cathode of the second diode; and a secondbattery comprising a positive terminal connected to the third terminalof the electronic switch and an anode of the first diode, and a negativeterminal connected to the second output terminal and an anode of thesecond diode; wherein in response to the input terminal receiving afirst control signal, the electronic switch is turned on, the first andsecond diodes are turned off, and the first and second batteries areconnected in series; and wherein in response to the input terminalreceiving a second control signal, the electronic switch is turned off,the first and second diodes are turned on, and the first and secondbatteries are connected in parallel.
 2. The battery control circuit ofclaim 1, wherein the electronic switch is an n-channelmetal-oxide-semiconductor field-effect transistor (MOSFET), the first,second, and third terminals of the electronic switch are a gate, asource, and a drain respectively.
 3. The battery control circuit ofclaim 1, wherein the first and second batteries are the same typerechargeable batteries with the same voltage.
 4. A battery controlcircuit comprising: an input terminal to receive control signals; firstand second output terminals to output power; first to fourth diodes;first and second electronic switches, each of the first and secondelectronic switches comprising a first terminal connected to the inputterminal, a second terminal, and a third terminal; a first batterycomprising a positive terminal connected to the first output terminaland cathodes of the first and second diodes, and a negative terminalconnected to the second terminal of the first electronic switch and acathode of the third diode; a second battery comprising a positiveterminal connected to the third terminal of the first electronic switchand an anode of the first diode, and a negative terminal connected tothe second terminal of the second electronic switch and a cathode of thefourth diode; and a third battery comprising a positive terminalconnected to the third terminal of the second electronic switch and ananode of the second diode, and a negative terminal connected to thesecond output terminal and anodes of the third and fourth diodes;wherein in response to the input terminal receiving a first controlsignal, the first and second electronic switches are turned on, thefirst to fourth diodes are turned off, and the first to third batteriesare connected in series; and wherein in response to the input terminalreceiving a second control signal, the first and second electronicswitches are turned off, the first to fourth diodes are turned on, andthe first to third batteries are connected in parallel.
 5. The batterycontrol circuit of claim 4, wherein each of the first and secondelectronic switches is an n-channel MOSFET, the first, second, and thirdterminals of each of the first and second electronic switches are agate, a source, and a drain respectively.
 6. The battery control circuitof claim 4, wherein the first to third batteries are the same typerechargeable batteries with the same voltage.